Chapter 7: Diesel Emissions

Diesel emission standards were not established until the __________.

• 1970s

• 1980s

• 1990s

• 2000s

Modern diesels emit close to __________ emissions.

• 10 parts per million (PPM)

• 1.5 parts per million (PPM)

• 20 parts per million (PPM)

• Zero

On- and off-highway vehicle emissions from the 1970s to present have been reduced by __________.

• 27%

• 13%

• 29%

• 39%

Technician A says legal emissions standards aim to reduce and eliminate the production of noxious substances from all internal combustion engines, except diesel-powered vehicles. Technician B says today's diesel engines also must comply with standards to reduce emissions. Who is correct?

• Technician A

• Technician B

• Both Technician A and Technician B

• Neither Technician A nor Technician B

Technician A says hydrocarbon emissions are formed as a result of fuel that have been burned completely. Technician B says fuels are classified as hydrocarbons because they are made of mostly hydrogen and carbon atoms. Who is correct?

• Technician A

• Technician B

• Both Technician A and Technician B

• Neither Technician A nor Technician B

Volatile organic compounds (VOCs) enter our atmosphere through evaporative emissions from hydrocarbon-based fuels. The chemical reaction creates ________.

• Ozone

• Nitrogen

• Carbon

• Particulate

Which of the following statements about carbon monoxide is correct?

• Carbon monoxide is created as a result of incomplete combustion of carbon-based fuels.

• Higher compression pressures and excess air used in diesel combustion limit carbon monoxide formation in diesels.

• Both A and B

• Neither A nor B

Which of the following statements about sulfates is correct?

• When diesel fuel is refined from petroleum oil that is pumped from the ground, varying quantities of sulfur naturally combine with oil.

• Burning sulfur contained in fuel produces sulfate (SOx) emissions, which can contribute to air pollution and acid rain.

• Both A and B

• Neither A nor B

Technician A says blow-by is the leakage of air past the piston rings into the crankcase. Technician B says that in any engine, blow-by occurs mostly during the compression stroke. Who is correct?

• Technician A

• Technician B

• Both Technician A and Technician B

• Neither Technician A nor Technician B

Low combustion temperatures and pressure, lack of oxygen, or insufficient burn time typically contribute to which emission?

• Carbon monoxide

• Carbon dioxide

• Oxides of nitrogen

• None of these is correct.